Fluid-pressure follow-up control system



. arch 27, 1951 H. E. ALTGELT gfiaggg FLUID PRESSURE FOLLOW-UP CONTROL SYSTEM Filed April 10, 1948 INVENTOR. hi5 ALTGELT' Patented Mar. 27, 1951 FLUID-PRESSURE FOLLOW-UP CONTROL SYSTEM Herman E. Altgelt, Moline, Ill., assignor to Deere & Company, Moline, 111., a corporation of Illinois Application April 10, 1948, Serial No. 20,272

6 Claims.

This invention relates to a control system for operating mechanism having a pair of relatively movable parts under control of a control element, such as a valve in a hydraulic system, and the improved system has for its principal object the provision of means for automatically controlling the valve, or equivalent control element, in response to predetermined relative movement of the operating parts.

The invention finds its greatest utility in connection with hydraulic control systems as used in tractor-propelled agricultural implements and machines. In a representative type of implement or machine of the class referred to, the tractor includes a fluid pressure source for supplying fluid under pressure to a motor which is operative to adjust a part of the implement or machine. In the case of a plow, the motor is operative to raise and lower the plow bottom and the control system is so arranged that a control valve is operative to regulate the extent to which the plow is raised or lowered, thus providing means for regulating the depth at which the plow will operate.

In a system including only the fundamentals of an arrangement of the type referred to above,

the depth at which the plow will operate (or the: conditions under which an equivalent part will function) is determined solely by manual positioning of a control lever; that is to say, the operator moves the control lever to cause the adjustable part to be moved to a desired position, and when the part reaches such position, the operator returns the control lever to neutral. In more refined systems, the arrangement includes means for automatically returning the control lever to neutral position at such time as the adjustable part has reached its desired position.

The invention is concerned primarily with improvements in systems including automatic follow-up or feed-back means for returning control members to neutral or inactive position after the parts under control thereof have reached predetermined operating or functioning conditions. It is an important object of the present invention to accomplish this desirable result by the use of fluid pressure means. It is a further object of the invention to include fluid-pressure means of the two-way type, so that the control element or valve may be returned to its inactive or neutral position from active positions at each side of said neutral position. A still further object of the invention involves the pro-- vision of a follow-up arrangement that may be readily applied to implements or similar opertailed description and accompanying sheet of.

drawing, in which the single figure shows, by

- way of example, and diagrammatically, the in-:

stallation of a fluid pressure follow-up system as adapted to a tractor-drawn plow.

The illustrated use of the system is based upon a preferred adaptation thereof and it should be understood that the invention is applicable to other situations and in other forms.

For the purposes of illustration and description, I have chosen a basic operating mechanism including a tractor-drawn plow comprising a tractor having a body III which is provided with a rearwardly extending drawbar H to which is pivotally connected at l2 the forward end 0!. a plow beam l3. The numeral l4 designates a plow bottom of conventional construction. The plow beam I3 is carried on a crank axle I5 on which is journaled a carrying wheel IS. The

crank axle Iii includes as an integral part thereof an upstanding lever arm portion H. The construction thus far described is generally conventional in all respects.

The tractor may be of the type having a builtin power control mechanism including a pump or other source of fluid under pressure contained in a housing carried on the tractor, such housing being designated generally by the numeral 20. The power source is in a main fluid pressure circuit which includes a fluid pressure motor, indicated generally by the numeral 21, comprising operating members in the form of a cylinder 22 and piston 23. The cylinder is connected to the upper end of the lever arm portion I1 on the crank axle I5; and the piston is connected to a bracket or support 24 extendin upwardly from and rigidly secured to the forward portion of the plow beam l3. The fluid motor 2| is preferably of the two-way type so that the piston 23 and the cylinder 22 are relatively movable in opposite directions under fluid pressure, the motor being connected by fluid-pressure transmitting means including a pair of conduits 25 and 28.

The conduits 25 and 26 thus provide means for delivering fluid under pressure to opposite ends of the cylinder 22, or at opposite sides 01. the piston .23, the construction in this respect being not dissimilar to conventional constructions.

The power source or power control means 20 may be of any conventional type, such as illustrated in co-pending application, Serial No. 626,626, filed November 5, 1945, now Patent No. 2,532,552, by Jirsa, Hansen, and Bopp. Such power control includes a control element, here represented by the numeral 30. In the particular application of the invention illustrated, the control element 30 is capable of manual control by means of a control member or lever 3| pivoted at 32, on a support including part of the tractor,

for fore and aft movement. The control lever 3I may include a releasable latch 33 cooperable with a notched sector 34 so that'the lever 3| is 'selectively settable in various positions of adjustment.

According to the invention, the control lever 3i and control element 30 (the latter being connected to suitable valve control means within the housing 26) are interconnected by means in the form of a device providing for either movement of the parts 3I and 30 together, or for movement relative to each other in opposite directions. The interconnecting means preferably takes the form of a two-way fluid pressure device designated generally by the numeral 35 and comprises a cylinder 35 and piston 31. The cylinder and piston provide members that are connectible together for movement simultaneously and that are further disconnectible from each other for movement separately, according to variations in fluid pressure impressed thereon or exhausted therefrom, the means for accomplishing which will be presently described.

. The fluid pressure device 35 is connected by a pair of fluid-pressure-transmitting means 38 and 39 to a second fluid-pressure-transmitting device 40carried on the plow. With respect to the location of the fluid-pressure device 40, it should be stated that it is not absolutely necessary that this device be mounted on the plow, for various other installations thereof are possible, the important requirement being only that the device 40 be so related to the device 2I as to respond to operation thereof. The fluid-pressure device 40 is of the two-way type and comprises a cylinder 4 -I and piston 42. The vpiston 42 is connected to an integral upward extension of the bracket or support 24 previously described. The cylinder 4I is-preferably connected to the cylinder 22 of the motor 2 I, as at 43. In a detailed construction of the type disclosed, the piston 42 is, in effect, connected to the piston 23 of the motor 2 I, whereas the cylinder M is connected to the cylinder 22 of the motor 2 I. It will be obvious that the cylinder and piston 4| and 42 may be connected to movable parts operated or adjusted by the motor 2 I. The type of construtcion illustrated is convenient for the purposes of illustration.

The fluid-pressure-transmitting means or conduits 38 and 39 serve to connect opposite ends or sides of the cylinder M in fluid-exchanging relationship respectively with opposite sides of the cylinder 36 of the fluid-pressure device 35. Although the means 38 and'39 are here shown as hoses, it will be obvious that they may assume any other form. These hoses are appropriately supported intermediate their connections to the cylinders, 35 and 41 by a support 45 carried at the forward end of the plow beam I3. Likewise, intermediate portions of the hoses 25 and 25 are so carried.

1 The operation of the system is as follows: The parts are shown in thedrawings in their intermediate positions. The piston 31, is midway between the opposite ends of the cylinder 36;

4 the piston 23 is midway between opposite ends of the cylinder 22; and the piston 42 is midway between opposite ends of the cylinder 4|. In

connection with the functioning and structure of the fluid-pressure devices 35 and 40, it will be noted that the fluid pressure circuit between mentioned type of hydraulic system should not be taken to limit the invention to the control- I ling of hydraulic systems alone.

It will be assumed that the operator desires to raise the plow bottom I4, in which case the system will be operated so that the crank axle I5 is rocked in a clockwise direction on its bearing on the plow beam I3. Accordingly, the operator releases the latch 33 on the control lever 3| and moves the lever to the left, the distance of movement depending upon how high the operator desires to raise the plow bottom I4. Having selected the desired amount of movement, the operator releases the latch 33 and the control lever 3| will become set in a differentangular position with respect to the quadrant 34. The component parts of all the fluid-pressure devices 2E, 35, and 49 will be static. Therefore, fluid or fluid pressure at opposite sides of the piston 31 in the chamber provided by the cylinder 36 of the device 35 will be balanced or held by the static relationship between the piston 42 in the chamber provided by the cylinder 4| of the device 40. Consequently, the fluid-pressure device 35 has its component parts interconnected in such manner that the device serves as a rigid link between the lever EI and the valve control element 3!], whereupon movementof the lever 3I to the left will simultaneously efiect movement of the control element 30 to the left. The valve (not shown) controlled by the element 30 will thus condition the power source to deliver fluid through the conduit 26 to the right hand end of the cylinder 22 of the fluid motor 2I, causing relative movement of the piston 23 and cylinder 22 such as to contract the motor 2| and shorten the distance between the lever arm I! and support 24, fluid being exhausted from the left hand end of the motor through the lower hose or conduit 25 back 'tothe reservoir (not shown) of the fluid pressure system, as is usual.

Contracting of the motor 2| effects a similar contracting of the fluid-pressure device 40, thus causing relative movement of the piston 42 and the cylinder 4I, whereupon the fluid-pressure device 40 serves as a pump for transmitting the efiects of fluid pressure through the upper hose or conduit 38 to the right hand end of the chamber provided by the chamber 36 of the fluidpressure device 35. The device 35 thus functions as a fluid-pressure motor and the piston 31 and cylinder '33 move relatively, thus contracting the distance between the lever 3| and the control element 3il,whereupon the latter is moved to the right, or returned to its inactive or neutral position. Such action of the control element 30 returns the control valve for the power source 23 to neutral position and the transmission of fluid under pressure to the mo-" asacgseo;

tor- 2 I; is: discontinued; whereupon all; the. parts regaint-heir staticpositions; Since thelcontrol: lever- 31' isset-"bythe latch- 33; it.will remain in, itslleftward position. Now, assuming: thatthe operator has not moved: the lever -3i to itsmaximum: leftward position, he: may shift the: lever.- further. to the left: andraise the plow bottom. M; an increased amount; whereupon the control: system will follow the proceduresetforth above..

Conversely, if the: operatordesires. to; lower: the; plow bottom, he willmovethe controllever 3 I to-the right, after: first releasing the-latch; 3:3. Since all the-parts start in their. static position, the fluid-pressure motor 3% efiects a rigid link:v between the lever 3.1 and control element; 311,. whereupon the control; element-1:. 36: follows; the lever-3| to the right; Thereupon,-.fiuid.pressure; is: transmitted through the lower fluid-pressure? transmitting conduit tothe left; hand endof' the cylinder-22of the-motor 2| therebyextemi:- ing': the motor 2 l: and rocking. the crank axle; I 5.: a. counterclockwise direction. Extension; of; the'motor 2| effectsa similar'extensionofthe device 4i], whichnow-operates-as a..fluid-pressure. pump in the other directionto1supp1yfluid1unv der. pressure through the means 39 to; the left. hand end of the. device 1 3 5,.fiuid being. exhausted from the right handyendzoftthe deviceltiithrough the conduit. 38 back to the; leftihand' end-,of the; cylinder. 4 I Consequently, .after'rthe,blow-bottom l4 has'zbeen lowered toanextent consistent with. theextent of angularposit-ioning ofithelever'th. the..-control.element' 30. will heimoved'totheleft;, or returned to.its:neutral orinactive. position,

From the foregoing.description; it:Wil1 beseen. that thecontrol system is both, flexibleand effie cient. and may be usedwithzprecision to effect -ad-.- justment of the implementor'machine part;.herez represented by the plow. bottoin- [4. Other objects and advantages-of? the inventionwillaum doubtedly occur to those versed in the art, and it is; not intended that the precise .details of construction and the description based. thereon. exclude: other adaptations of 'the :invention, for-it is ob:

viousthat numerous modifications and. alterae tions may be made inithe.preferredform.of. the invention illustrated Withoutdeparting from: the spirit. and scope offtheinvention asdefined in the; appended claims.

I claim:

11 In a=system of: the classdescribed including. parts relatively movable= in opposite directions: from onestatic position to other static positions and operating means for rendering said parts static or relatively" movableincluding: a control-element movable in either'directionfrom an'inactive position to active-positions and return for controlling the operating means, the improv ment residing in mechanism for moving the control element from its inactive position to an active position and for automatically returning said element to inactive position after predetermined relative movement of said parts, comprising: a control member selectively settable in different positions; a first two-way fluid-pressure device, including a piston and a cylinder connected respectively to the aforesaid parts; a second twoway fluid-pressure device including a cylinder and piston, one connected to the control member and the other to the control element; a first fluidpressure-transmitting conduit connecting one side of the first cylinder with the one side of the second cylinder; and a second fluid-pressuretransmitting means connecting the other side of the first cylinder to the other side of the second cylinder; said fiuidepressure" devices: being active ,when thexaforesaid;partsaarexstaticso that:

thesecond; device operates asgzarigid linkrbetween the control'member; and-2 the controlzele ment. to provide for moving of; the: latter by the. former in either direction, relative movement of the cylinder and piston in the first fluidspressure the .control member;

2. In a system of;the;classadescribed including parts relatively: movable in" opposite: directions from one ,static position to; other static positions and. operating: means for; rendering saidparts static, or relatively movable; including a control.

element" movableuin either direction from an: int-- active position to lactivei positions and returnafor controlling: the: operating means; the improves ment residing in mechanism-forqmoving tl'iecon trol ieiement'fromits inactive position t'o an active;

position andfor automatically returning said element to inactive position after predetermined relative movement of said parts, comprising: a.

control member selectively settable in different positions; a first two-way fluid-pressure device comprising a pump connected to at least" one of the aforesaid'parts and capable of discharging or' receiving fluid alternately-at either side thereof depending upon the direction of relative movement-of said parts; flSfiCOIld'tWO-W-ELY fluid-pres sure device comprising-'a motor having a pair of I members movable relative to-each other in op-- posite directions and'connected respectivelytothecontrol member'and to the control element; one

of said motor members includinga chainberenclosing the other motor memberand' capable of receiving or discharging fluid at either side-0f said other motormember; and first andsecond fluid-- pressure-transmitting means connected respect ively between oppositesides of'said devices; said iiuid pressure devices being inactive when theaforesaid-parts are static sothat-the-second de vice operates as a-rigid link" between the control member and the control elementto provide for' moving-of thelatter by-thefbrmerih either-di rection; operation of thefirst device asa pump' to discharge fluid pressure at one side or 'theother thereof 'in response to relative movement of the aforesaid parts: in one direction orthe other eficctuating the transmission of'fluid-pressure-to one side or the other-of'the second-device to move the members thereof relative to'each 5 other-in onedirection or the otherj-and hence-to move the 1' control element relative to the control member 'in' one direction or theiother:

3. In a systeinof'theclassdescribedincluding parts. relatively movable in opposite directions--v from one static position to other :st'atie positions" and operating means" for renderingsaid parts" static or relatively movable including a control element movable in either direction from an inactive position to active positions and return for controlling the operating means, the improvement residing in mechanism for moving the control element from its inactive position to an active position and for automatically returning said element to inactive position after predetermined relative movement of said parts, comp-rising: a

control member selectively settable in different positions; a fluid-pressure means including a two- Way cylinder and piston device connected between the control member and the control element; means connected to at least one of the aforesaid parts and operative in response to a static condition of said parts to hold fluid pressure in said cylinder on both sides of said piston so that said device serves as a rigid link between the control member and the control element providing for movement of the latter by the former in either direction to an active position; and means connected to at least one of said parts and operative respectively in response to relative movement of said parts in one direction or the other to impress and exhaust fluid-pressure on one side or the other of said piston to move the control element relative to the control member.

4. In a system of the class described including parts relatively movable in opposite directions from one static position to other static positions and operating means for rendering said parts static or relatively movable including a control element movable in either'direction from an inactive position to active positions and return for controlling the operating means, the improvement residing in mechanism for moving the control element from its inactive position to an active position and for automatically returning said element to inactive position after predetermined relative movement of said parts, comprising: a control member selectively settable in different positions; a two-way fluid-pressure device having a pair of members movable relative to each other in opposite directions for expansion or contraction and connected respectively to the control member and to the control element, one of said members being a fluid-receiving and eX- hausting chamber and the other being carried therein, said chamber including a port at each side of said other member for receiving or exhausting fluid pressure; means connected to at least one of the aforesaid parts and operative in response to a static condition of said parts to hold a fluid-pressure balance on both of said parts so that said device serves as a rigid link between the control member and the control element providing for movement of the latter by the former in either direction to an active position; and means connected to at least one of said parts and operative respectively in response to movement of said parts relative to each other in one direction or the other to impress and exhaust fluid-pressure on one side or the other of said member in the chamber through one or the other of said ports to expand or contract said device and thus to move the control element in one direction or the other relative to the control member.

In a system of the class described including parts relatively movable in opposite directions from one static position to other static positions and operating means for rendering said parts static or relatively movable including a control element movable in either direction from an inactive position to active positions and return for controlling the operating means, the improvement residing in mechanism for moving the control element from its inactive position to an active position and for automatically returning said element to inactive position after predetermined relative movement of said parts, comprising: a control member selectively settable in different positions; an interconnecting device between the control member and the control element including a pair of members interconnectible for movement together to serve as a rigid link means between the control member and control element so that the former may move the latter in either direction from inactive position, said pair of members being disconnectible for movement relative to each other in opposite directions so that the control element may return to inactive position from either direction relative to the control member; and'means including a two-way fluid-pressure device connected to at least one of the aforesaid parts and to the interconnecting device and operative in response to a static condition of said parts to hold said pair of members in interconnected relation, and operative in response to relative movement of said parts in one direction or the other to effect disconnection of said pair of members and to move one of said members relative to the other in one direction or the other.

6. In a system of the class described including parts relatively movable in opposite directions from one static position to other static positions and operating means for rendering said parts static or relatively movable including a control element movable in either direction from an inactive position to active positions and return for controlling the operating means, the improvement residing in mechanism for moving the control element from its inactive position to an active position and for automatically returning said element to inactive position after predetermined relative movement of said parts, comprising: a control member selectively settable in different positions; operating means between the control member and control element operative to condition the two for movement together in either direction when the aforesaid parts are in a static condition, and operative to condition the control element for return movement from either direction to inactive position relative to the control member; and means including a two-way fluid-pressure device connected to one of the aforesaid parts and to the control element and operative in response to relative movement of said parts in one direction or the other to return the control element to inactive position from one direction or the other relative to the control member.

HERMAN E. ALTGELT.

No references cited. 

